In a general radio communication system, an evolved Node B (eNB) may assign uplink resources to a User Equipment (UE), in order to enable the UE to perform uplink transmission to the eNB. In addition, a UE having data to be transmitted in uplink may transmit a Scheduling Request (SR) to an eNB to request uplink resource assignment.
Scheduling request methods include methods based on random access of a UE and methods enabling a UE to use a dedicated channel.
In the random access method, since a plurality of UEs share resources for a scheduling request, resource use efficiency is high, but scheduling requests of a plurality of UEs may collide with each other and thus time required to solve such collisions may result in considerable delays. In the method using the dedicated channel, since discriminable resources for a scheduling request are assigned to each UE, collision between UEs does not occur, but the amount of resources required for the scheduling request may be increased.
In addition, in the case where one UE transmits scheduling requests for a plurality of uplink transmissions (that is, a plurality of uplink traffic flows) to an eNB, each scheduling request for each uplink traffic flow may be transmitted to the eNB.